[Gmsh] Incorrect char length (and a host of perhaps related problems)

[Anthony Costa]

I am receiving an odd error message saying
Error   : Incorrect char. length lc = 0: using default instead

This is patently false in my mesh. The value is well defined and of
proper order.

The mesh is a 3D box with a cylindrical capillary travelling through
the middle of the 3D box.

After the returned errors, I get a series of other errors, which
eventually lead to the failure of the mesh compilation. This is true
at a variety of characteristic lengths. One of these is:
Error   : 3 identical points in Qtest

There is obviously something I have overlooked here. Any advice would
be much appreciated. GEO file attached. I am using a recent nightly
build: 20080208.

Thanks!
Anthony

---

// conver to meters
ctm = 0.001;

// characteristic length
lc = 0.01*ctm;

// resolved length
rc = 0.01*ctm;

negx = 0*ctm;
negy = -50*ctm;
negz = -50*ctm;
posx = 250*ctm;
posy = 50*ctm;
posz = 50*ctm;

Point(1) = {negx, negy, negz, lc};
Point(2) = {posx, negy, negz, lc};
Point(3) = {posx, posy, negz, lc};
Point(4) = {negx, posy, negz, lc};
Point(5) = {negx, negy, posz, lc};
Point(6) = {posx, negy, posz, lc};
Point(7) = {posx, posy, posz, lc};
Point(8) = {negx, posy, posz, lc};
Line(1) = {4,3};
Line(2) = {3,7};
Line(3) = {7,8};
Line(4) = {8,4};
Line(5) = {4,1};
Line(6) = {1,5};
Line(7) = {5,8};
Line(8) = {5,6};
Line(9) = {6,2};
Line(10) = {2,1};
Line(11) = {2,3};
Line(12) = {7,6};

// center of sprayer
Point(20) = {0,0,0,rc};

// length of sprayer into the box
spraylength = 25*ctm;

// inner capillary diameter
incapdiameter = .25*ctm;

// outer capillary diameter
outcapdiameter = 1.5875*ctm;

// inner and outer spray points on box wall
Point(34) = {0,-0.5*outcapdiameter,0,rc};
Point(35) = {0,0.5*outcapdiameter,0,rc};
Point(36) = {0,0,-0.5*outcapdiameter,0,rc};
Point(37) = {0,0,0.5*outcapdiameter,0,rc};

// circle definitions
Circle(17) = {37,20,34};
Circle(18) = {34,20,36};
Circle(19) = {36,20,35};
Circle(20) = {35,20,37};

// major plane surfaces at sim boundaries
Line Loop(37) = {1,2,3,4};
Plane Surface(38) = {37};
Line Loop(39) = {1,-11,10,-5};
Plane Surface(40) = {39};
Line Loop(41) = {10,6,8,9};
Plane Surface(42) = {41};
Line Loop(43) = {7,-3,12,-8};
Plane Surface(44) = {43};
Line Loop(45) = {11,2,12,9};
Plane Surface(46) = {45};
Line Loop(47) = {4,5,6,7};
Line Loop(48) = {19,20,17,18};
Plane Surface(49) = {47,48};

// expansion of outer capillary region into box
Extrude {spraylength,0,0} {
  Line{20,19,18,17};
  Point{20};
}

// creation of inner capillary termination region
Point(80) = {spraylength,-(1/2)*incapdiameter,0,rc};
Point(81) = {spraylength,(1/2)*incapdiameter,0,rc};
Point(82) = {spraylength,0,-(1/2)*incapdiameter,0,rc};
Point(83) = {spraylength,0,(1/2)*incapdiameter,0,rc};

// circles in inner capillary termination region
Circle(67) = {81,39,83};
Circle(68) = {83,39,80};
Circle(69) = {80,39,82};
Circle(70) = {82,39,81};

// creation of outer and inner capillary regions with normal in
capillary extension direction
Line Loop(71) = {50,62,58,54};
Line Loop(72) = {67,68,69,70};
Plane Surface(73) = {71,72};
Plane Surface(74) = {72};
Surface Loop(75) = {44,49,38,40,46,42,61,57,53,65,73,74};

// the simulation volume
Volume(76) = {75};

-- 
Anthony B. Costa
Purdue University
Department of Chemistry
560 Oval Drive, #365
West Lafayette, IN 47907